Polymerizability of methyl α-substituted acrylates containing methoxycarbonyl groups

Dimethyl 4-methyl-1-pentene-2,4-dicarboxylate ( 3 ) and trimethyl 4-methyl-1-octene-2,4,7-tricarboxylate ( 4 ) are not radically homopolymerizable. Dimethyl 1-hexene-2,4-dicarboxylate ( 5 ) polymerizes slowly to yield a small amount of oligomers. Homopolymerization of dimethyl 1-butene-2,4-dicarboxylate ( 6 ) affords a high-molecular-weight polymer. Radical copolymerization of these methyl α-substituted acrylates (M₂) with styrene (M₁) was carried out at 60°C using AIBN, and the following monomer reactivity ratios were obtained; 3 : r₁ = 0,983, r₂ = 0,000; 4 : r₁ = 0,938, r₂ = 0,000; 5 : r₁ = 0,672, r₂ = 0,119; 6 : r₁ = 0,566, r₂ = 0,195. The polymerizability of these methyl acrylate derivatives is influenced by the steric effect of the α-substituents.